Combination of Pre-Pulse and Constant Pumping Rate Hydraulic Fracturing for Weakening Hard Coal and Rock Mass

Cheng, Qingying; Huang, Bingxiang; Shao, Luying; Zhao, Xinglong; Chen, Shuliang; Li, Haoze; Wang, Changwei

doi:10.3390/en13215534

Cited by 21 publications

(11 citation statements)

References 23 publications

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“…(1) Using pulse hydraulic fracturing technology, [17][18][19] a dense network of cracks is formed in the hard roof directly above the coal pillar, fully crushing this area. By using directional hydraulic fracturing technology, 20,21 the hanging roof of the goaf on both sides of the coal pillar is cut off, effectively optimizing the stress above the coal pillar and reducing the source of stress.…”

Section: The Idea Of Using Hydraulic Fracturing To Control Stress Con...mentioning

confidence: 99%

“…(2) By using pulse hydraulic fracturing technology, [17][18][19] a dense network of cracks is formed within the coal pillar, fully crushing this area, reducing the stiffness of the coal pillar, and thereby reducing the bearing capacity of the coal pillar. (3) By using pulse hydraulic fracturing technology, [17][18][19] a dense network of cracks is formed in the hard floor directly below the coal pillar, fully crushing this area, thereby weakening the ability to transmit stress concentration.…”

Section: The Idea Of Using Hydraulic Fracturing To Control Stress Con...mentioning

confidence: 99%

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Hydraulic fracturing method for relieving stress concentration in remaining coal pillar in overlying goaf

Shao,

Huang,

Zhao

et al. 2024

Energy Science & Engineering

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The stress concentration caused by the presence of the remaining coal pillar in the overlying goaf can easily cause large deformation of the roadway in the lower seam and other problems. To solve this problem, the reasons for stress concentration caused by the remaining coal pillar in the overlying goaf were analyzed. A hydraulic fracturing method for relieving stress concentration has been proposed. By using hydraulic fracturing technology to remove the hanging roof on both sides of the coal pillar and weaken the coal pillar system, high stress is transferred to the goaf. The degree of stress concentration in coal pillars and surrounding rock of roadway can be reduced by 47% and 26%, respectively. This method can also solve the stress concentration problem of the remaining ore pillar in the overlying goaf of the metal ore. This method has been applied in the coal mine. The deformation of the surrounding rock of the test roadway after hydraulic fracturing has been reduced by more than 60%.

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Section: The Idea Of Using Hydraulic Fracturing To Control Stress Con...mentioning

confidence: 99%

Section: The Idea Of Using Hydraulic Fracturing To Control Stress Con...mentioning

confidence: 99%

Hydraulic fracturing method for relieving stress concentration in remaining coal pillar in overlying goaf

Shao,

Huang,

Zhao

et al. 2024

Energy Science & Engineering

Self Cite

View full text Add to dashboard Cite

show abstract

“…e integrity of the coal seam in water injection section is damaged under a certain water pressure. Affected by the mechanical properties [10][11][12], water injection method [13,14], and distribution of rock strata [15][16][17], the propagation form of coal fractures will be different [18,19]. Coal damage caused by water pressure changes the stress distribution of the roadway sidewall [20,21].…”

Section: Introductionmentioning

confidence: 99%

A Study on Stress Redistribution of Roadway Sidewall after Hydraulic Fracturing in Coal Bumps Prevention

Yin

Tang

Zhang

et al. 2022

Shock and Vibration

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Hydraulic fracturing is an effective mean to prevent coal bumps in deep coal mining. The calculation of stress redistribution of coal sidewall after hydraulic fracturing can evaluate the fracturing effect and provide a reference for the hydraulic fracturing scheme design. In this paper, a theoretical model of stress redistribution of roadway sidewall after hydraulic fracturing is established with considering the effect of crushing zone. And the influences of the water injection length and the fracturing radius on the stress redistribution of roadway sidewall are investigated. The results show that the water injection section should be set at a deeper position with considering the existence of the crushing zone. The coal roadway sidewall after hydraulic fracturing is divided into five zones: the crushing zone, the shallow plastic zone, the pressure relief zone, the deep plastic zone, and the elastic zone. The stress redistribution law is obviously affected by the water injection section length and fracturing radius. With the increase of water injection length or fracturing radius, the pressure relief effect is more evident, but the axial force of rockbolt increases gradually. In order to acquire a better pressure relief effect, the matching of the water injection length and the fracturing radius should be considered crucially in the hydraulic fracturing design for preventing coal bumps.

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“…With the increasing proportion of complex coal seams [1][2][3][4], the efficiency of traditional mechanical coal mining methods is getting lower. Since most of the complex coal seams are harder, it is difficult to achieve good results by increasing the size or power of the cutting mechanism under such conditions.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Study on Crushing Properties of Hard Coal Using Impacting-Cutting Technique

Zhang

Wang

Tian

2022

Shock and Vibration

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The reserves of high-quality coal seams have been greatly reduced in recent years, and the low efficiency of traditional cutting methods in hard coal seams has become a problem for the coal production industry. In order to improve the mining efficiency, an impacting-cutting technique was proposed in this study. A drum modification model with picks impact function was established, and crushing properties of the impacting-cutting drum at f4, f5, and f6 coal hardness were simulated using the discrete element method. The simulation results show that the impacting-cutting drum has higher coal crushing efficiency, lower drum force, and more stable cutting processes than the traditional drum. It shows that hard coal might be effectively reduced by the impacting-cutting technique to reduce the difficulty of mining, and reflected the applicability in hard coal seams. Meanwhile, a simplified test device for the impacting-cutting technique was designed. And the actual coal crushing performance was tested. The test results show that the force of the cutting mechanism in the impact mode is lower than that of the nonimpact mode, and the force is more stable. It proves that the impacting-cutting technique has a higher applicability of hard coal seams than the traditional technique.

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Combination of Pre-Pulse and Constant Pumping Rate Hydraulic Fracturing for Weakening Hard Coal and Rock Mass

Cited by 21 publications

References 23 publications

Hydraulic fracturing method for relieving stress concentration in remaining coal pillar in overlying goaf

Hydraulic fracturing method for relieving stress concentration in remaining coal pillar in overlying goaf

A Study on Stress Redistribution of Roadway Sidewall after Hydraulic Fracturing in Coal Bumps Prevention

Numerical and Experimental Study on Crushing Properties of Hard Coal Using Impacting-Cutting Technique

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